I agree with dsmith3 method except for the holding tanks and water heater. Even if you dump before leaving the campground it is practically impossible to be sure that the tanks are truly empty. I don't want to get home, open the black dump valve and dump any remaining black water. I don't mind the grey and galley tanks dumping on my RV pad so I will leave them open. I leave the black closed and add a 1/2 gallon or so of the pink stuff. I also drain the water heater.
We camp throughout the winter, any time we want to go, so any extensive winterizing-dewinterizing is not practical.
My TT has an enclosed heated underbelly so most years I don't do any winterizing at all. On the few nights it is forecast to freeze I just turn the furnace on and set the thermostat to a low temp and let it take care of the cold. Some nights I have even slept out there.